1. Field of the Invention
This invention relates to a coloration analyzing apparatus and a coloration analyzing method for performing a quantitative analysis or a qualitative analysis of an analyte (i.e., a substance to be analyzed), which is contained in a test body solution.
2. Description of the Related Art
Recently, for examinations of external diagnostic medicines, poisons, and the like, there have been proposed various devices for feeding test body solutions, which have the possibility of containing analytes, to test pieces, and easily and quickly making examinations with respect to the analytes by use of immunochromatographic techniques. (Reference may be made to, for example, U.S. Patent Application Publication No. 20090093968.) For example, an insoluble support constituted of a porous material is prepared. The insoluble support is provided with a specific region (a test line), to which a first antibody that specifically binds with an analyte (e.g., an antigen) has been fixed. Also, a test body solution, which contains a mixture of a labeling second antibody that specifically binds with the analyte, and a test body having the possibility of containing the analyte, is developed through the insoluble support. As a result, an antigen-antibody reaction among the analyte, the first antibody, and the second antibody arises in the test line, and the test line is thus colored or develops color and comes into a coloration state. By observing the coloration state of the test line, it is quantitatively or qualitatively (negative/positive) analyzed whether the analyte is or is not present in the test body solution.
Also, in order for the coloration state of the test line to be detected quickly and with a high sensitivity, it has been proposed to perform amplification processing by use of an amplifying agent. (Reference may be made to, for example, U.S. Patent Application Publication No. 20090181470.) In U.S. Patent Application Publication No. 20090181470, it is disclosed that, with processing wherein, after the aforesaid test body solution has been developed through the insoluble support, and wherein an amplifying agent containing a metal ion, such as a silver ion, is developed through the insoluble support, the metal ion is bound with the complex of first antibody—analyte (antigen)—second antibody on the test line and thus amplifies the coloration state. It is also disclosed that a washing liquid is developed through the test region and its neighboring regions before the amplification processing is performed, and that noise due to the labeling substance, which is present at background regions, is thereby suppressed.
However, the test body solutions developed through the insoluble support have viscosities varying for different test body solutions. Some test body solutions may have a high viscosity, and other test body solutions may have a low viscosity. In cases where a predetermined quantity of the washing liquid is developed for performing the washing in the washing step, it often occurs that sufficient washing is not performed with respect to a test body solution having a high viscosity. If the amplification processing is performed in this state, the problems will occur in that washing non-uniformity and background noise arise, and in that the accuracy with which the analyte is analyzed becomes low.